ERK1 (K71A) Recombinant Protein

The protein encoded by this gene is a member of the MAP kinase family. MAP kinases, also known as extracellular signal-regulated kinases (ERKs), act in a signaling cascade that regulates various cellular processes such as proliferation, differentiation, and cell cycle progression in response to a variety of extracellular signals. This kinase is activated by upstream kinases, resulting in its translocation to the nucleus where it phosphorylates nuclear targets. Alternatively spliced transcript variants encoding different protein isoforms have been described. [provided by RefSeq, Jul 2008]

Function: Serine/threonine kinase which acts as an essential component of the MAP kinase signal transduction pathway. MAPK1/ERK2 and MAPK3/ERK1 are the 2 MAPKs which play an important role in the MAPK/ERK cascade. They participate also in a signaling cascade initiated by activated KIT and KITLG/SCF. Depending on the cellular context, the MAPK/ERK cascade mediates diverse biological functions such as cell growth, adhesion, survival and differentiation through the regulation of transcription, translation, cytoskeletal rearrangements. The MAPK/ERK cascade plays also a role in initiation and regulation of meiosis, mitosis, and postmitotic functions in differentiated cells by phosphorylating a number of transcription factors. About 160 substrates have already been discovered for ERKs. Many of these substrates are localized in the nucleus, and seem to participate in the regulation of transcription upon stimulation. However, other substrates are found in the cytosol as well as in other cellular organelles, and those are responsible for processes such as translation, mitosis and apoptosis. Moreover, the MAPK/ERK cascade is also involved in the regulation of the endosomal dynamics, including lysosome processing and endosome cycling through the perinuclear recycling compartment (PNRC); as well as in the fragmentation of the Golgi apparatus during mitosis. The substrates include transcription factors (such as ATF2, BCL6, ELK1, ERF, FOS, HSF4 or SPZ1), cytoskeletal elements (such as CANX, CTTN, GJA1, MAP2, MAPT, PXN, SORBS3 or STMN1), regulators of apoptosis (such as BAD, BTG2, CASP9, DAPK1, IER3, MCL1 or PPARG), regulators of translation (such as EIF4EBP1) and a variety of other signaling-related molecules (like ARHGEF2, FRS2 or GRB10). Protein kinases (such as RAF1, RPS6KA1/RSK1, RPS6KA3/RSK2, RPS6KA2/RSK3, RPS6KA6/RSK4, SYK, MKNK1/MNK1, MKNK2/MNK2, RPS6KA5/MSK1, RPS6KA4/MSK2, MAPKAPK3 or MAPKAPK5) and phosphatases (such as DUSP1, DUSP4, DUSP6 or DUSP16) are other substrates which enable the propagation the MAPK/ERK signal to additional cytosolic and nuclear targets, thereby extending the specificity of the cascade. Ref.11 Ref.13 Ref.14 Ref.15 Ref.18 Ref.19 Ref.22 Ref.24 Ref.25 Ref.26 Ref.28 Ref.36

Catalytic activity: ATP + a protein = ADP + a phosphoprotein.

Cofactor: Magnesium

By similarity.

Enzyme regulation: Phosphorylated by MAP2K1/MEK1 and MAP2K2/MEK2 on Thr-202 and Tyr-204 in response to external stimuli like insulin or NGF. Both phosphorylations are required for activity. This phosphorylation causes dramatic conformational changes, which enable full activation and interaction of MAPK1/ERK2 with its substrates. Dephosphorylated and inactivated by DUSP3, DUSP6 and DUSP9. Ref.19 Ref.40

Subunit structure: Binds both upstream activators and downstream substrates in multimolecular complexes. Found in a complex with at least BRAF, HRAS1, MAP2K1/MEK1, MAPK3 and RGS14

By similarity. Binds to HIV-1 Nef through its SH3 domain. This interaction inhibits its tyrosine-kinase activity. Interacts with ADAM15, ARRB2, CANX, DAPK1 (via death domain), HSF4, IER3, MAP2K1/MEK1, MORG1, NISCH, and SGK1. Interacts with PEA15 and MKNK2

By similarity. MKNK2 isoform 1 binding prevents from dephosphorylation and inactivation

By similarity. Interacts with TPR. Ref.12 Ref.15 Ref.17 Ref.19 Ref.20 Ref.23 Ref.28 Ref.30 Ref.31 Ref.33 Ref.38 Ref.40

Subcellular location: Cytoplasm. Nucleus. Note: Autophosphorylation at Thr-207 promotes nuclear localization. Ref.17 Ref.40

Domain: The TXY motif contains the threonine and tyrosine residues whose phosphorylation activates the MAP kinases. Ref.17

Post-translational modification: Phosphorylated upon KIT and FLT3 signaling

By similarity. Dually phosphorylated on Thr-202 and Tyr-204, which activates the enzyme. Ligand-activated ALK induces tyrosine phosphorylation. Dephosphorylated by PTPRJ at Tyr-204. Ref.16 Ref.29 Ref.36 Ref.37 Ref.40 Ref.48

Sequence similarities: Belongs to the protein kinase superfamily. CMGC Ser/Thr protein kinase family. MAP kinase subfamily.Contains 1 protein kinase domain.